1. Field of the Invention
This invention relates to mechanical couplings such as utilized to operably couple an actuatable device having a shiftable component with the shiftable part of an actuating mechanism spaced from the device. More particularly, the invention is concerned with providing improved apparatus for maintaining the tautness of such couplings under usage conditions involving wear or aging effects that would otherwise tend to loosen or create undesirable "slack" in the coupling. Apparatus of the general class involved have sometimes been referred to as "slack adjuster" or "slack take-up" devices.
2. Description of the Prior Art
Known prior devices of the same general class include those proposed in U.S. Pat. Nos. 711,750 (Wilson), 1,477,891 (Osborn), 1,590,502 (Djurson), 1,592,969 (DeCamp), 1,811,913 (Browall), and 1,837,473 (Neven). The state of the art represented by such prior patents is believed characterized by a number of limiting factors and general rationale incompatible with providing a general purpose device that would be reliable yet sufficiently small, economical and versatile to be used in diverse applications such as in ordinary bicycle brakes. The noted prior devices were apparently intended for utilization primarily or exclusively in massive systems such as railroad air brake equipment, are essentially built into a fluid cylinder actuator or otherwise configured to form a part of a rigid linkage system, are inherently ill-adapted for use in many cable coupled systems, and are relatively heavy, complex, expensive to manufacture and of nature likely to require considerable maintenance. Such prior art further seems to manifest a focusing of primary innovative effort upon the matter of preventing retrograde movement of the turnbuckle components, resulting in its resort both to various forms of unnecessary ratchet mechanisms and to relatedly special or aberrated forms of turnbuckle components apparently intended to accommodate to the particular form of ratchet mechanism proposed, which is a problem solved more straight-forwardly by this invention through a construction that simply precludes such retrograde motion with the same components that provide the desired intermittent take-up motion.